1. Field of the Invention
The present invention relates to means for the interconnection of two devices provided with telephone line connections, preferably a personal computer and a telefax machine.
2. Description of the Prior Art
Personal computers, PC's, especially portable types, are more and more commonly being equipped with telefax modems allowing them to send and receive printouts as telefax documents via the common telephone system. In reality this is a type of remote print-out or remote scanning of documents as an alternative to the ordinarily connected printer or picture scanner. Often, and especially when using a portable computer outside the ordinary work place, a suitable printer is not available, or the possibly available printer is not properly interfaced or there is no suitable software driver for the possibly available printer. In such cases it appears reasonably obvious to utilize the nowadays commonly available telefax machines for the purpose of printout or scanning, especially as a temporary solution away from the office. This can always be done, provided that the computer is equipped with a fax modem, by using the fax function as intended, i e by calling up the intended fax machine via its telephone connection. This procedure however, requires the availability of two separate telephone lines close to one another. Furthermore, these lines are tied up for extended periods during the printout of long documents.
If one tries to interconnect the devices directly to one another by joining its telephone line connectors, one will find that the devices will not work as intended because they are internally provided with sensing devices to make sure they are connected to properly functioning telephone lines by the detection of the calling tone and line voltage. Previously a device is as described in U.S. Pat. No. 4,991,200, was used to simulate the ring signal function and thereby to order the fax machine via a relay signal routing system to start receiving whatever information the computer transmits.